This invention relates to immune complex isolation.
It is known to isolate circulating immune complexes from sera by contacting the sera with a component that binds to the immune complexes and may be removed with them. It has been proposed to isolate the circulating immune complexes for use in diagnosing diseases or detecting auto-immune disorders or for research purposes by correlating the appearance of certain circulating immune complexes and their levels with diseases or with other factors to be detected or identified.
In one prior art technique, immunoglobulin complexes are precipitated with polyethylene glycol. This technique has a disadvantage in that, under many circumstances, the amount of monomeric immunoglobulin precipitated is so large that determinations based on total precipitation of monomeric immunoglobulin and immune complexes are difficult because changes in the amount precipitated are not sufficiently representative of the immune complexes present in the subject. Moreover, if the sample is plasma rather than serum, other precipitates further complicate the analysis.
In another prior art technique for isolating circulating immune complexes, the circulating immune complex is bound to bovine conglutenin through fixed C3 complement components. In still another technique, the circulating immune complex is bound to human Clq which has been immobilized in an affinity chromatographic column and then eluted with a diaminoalkyl compound.
These prior art techniques have several disadvantages such as: (1) they do not isolate a sufficient quantity of curculating immune comples to enable an analysis of the antigen moiety; (2) they are not sufficiently specific; and (3) they are relatively expensive and difficult to use because they require specialized equipment.